FDA probes TG Therapeutics' Ukoniq over potential for elevated death risks 1 year after drug's approval

Hyped as a safer version of other drugs in its class upon its approval last February, TG Therapeutics’ Ukoniq appeared on its way to differentiating itself in certain types of lymphoma.

But a year later, Ukoniq is under scrutiny as the FDA is investigating whether it increases the risk of death. The concerns stem from findings in a phase 3 trial testing the drug in combination with TG Therapeutics’ monoclonal antibody ublituximab in people with chronic lymphocytic leukemia (CLL).

Ukoniq is marketed to treat two other types of lymphoma—relapsed or refractory marginal zone lymphoma (MZL) and follicular lymphoma (FL). An approval to treat CLL, which is much more prevalent, would be a major coup for TG as Ukoniq is its only FDA-sanctioned drug.

“Because of the seriousness of this safety concern and the similarities between the two types of cancer for which this drug is approved and the type of cancer that was studied in the clinical trial, the FDA is alerting patients and health care professionals that FDA is re-evaluating this risk against the benefits of Ukoniq for its approved uses,” the announcement said.

RELATED: TG tumbles as FDA still hasn't found what it's looking for in U2 leukemia combo, orders advisory committee

The FDA in November said it would hold an advisory committee meeting on the combo treatment, which is nicknamed U2. Now, the FDA says an early analysis of overall survival from the Unity-CLL trial has raised red flags. The trail measured U2 against Roche’s combo of Gazyva and chemo drug chlorambucil.

“The results showed a possible increased risk of death in patients receiving the combination of Ukoniq and the monoclonal antibody compared to the control arm,” the FDA wrote. “Those receiving the combination of Ukoniq and the monoclonal antibody also experienced more serious adverse events than those in the control arm.”

The FDA has suspended enrollment of new patients in other ongoing clinical trials of Ukoniq while it continues to review the Unity findings, it said.

Ukoniq is a member of the PI3K-delta inhibitor class. Others in the class that are on the market—including Gilead’s Zydelig (Gilead) and Verastem’s Copiktra—carry black box warnings for side effects. When Ukoniq gained its green light, it’s label included warnings, but not in a black box.

RELATED: Watch out, Gilead: TG Therapeutics wins FDA nod for potentially safer Zydelig rival

Upon its approval, Evaluate Pharma predicted sales of the drug would reach $296 million by 2026. An approval in CLL would dramatically accelerate its use according to Cantor Fitzgerald analyst Alethia Young, who saw the potential for $1.6 billion in peak sales.